NONCOLLINEAR MAGNETIC-STRUCTURES OF FE-BASED AMORPHOUS-ALLOYS

Neutron scattering techniques have been used to study the structure of amorphous materials. The experiment used both polarized incident and scattered neutron beams and so did not need to assume a collinear magnetic structure. Five different Fe-based amorphous materials were studied and the structures were found to differ. In the case of Fe83B17 the spins are canted in a magnetic field of 2 T about 30-degrees from the applied direction. The transverse components have only very short-range order. Other materials show less canting. Fe-Ni amorphous materials shows a large amount of disorder in the spin directions and in the aligned moment. This suggests that the Ni atoms do carry a magnetic moment but that it may be largely misaligned to the Fe moment. Inelastic measurements of the density of magnetic states show a very different distribution to that expected from a powdered ferromagnet. This may arise from 'hidden' short-wavelength excitations.